Azo dyestuffs



United States Patent 3,097,198 AZO DYESTUFFS Brian Ribbons Fishwick and James Wardleworth, Manchester, England, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain N0 Drawing. Filed Jam, 1960, Ser. No. 5,378 Claims priority, application Great Britain Feb. 10, 1959 4 Claims. (Ci. 260-2071) This invention relates to new azo dyestuffs and more particularly it relates to new water-insoluble azo dyestuiis which are valuable for the dyeing of artificial textile materials.

According to the invention we provide the new waterinsoluble azo dyestuffs of the formula wherein D represents a monoor bi-cyclic aromatic nucleus, R stands for a lower alkyl or :aralkyl group, either of which may carry non-ionogenic substituent-s, or for the group A C-OA (X) n A represents a CH or CH CH group, A repre sents a saturated dior tri-valent aliphatic radical of from 1 to 4 carbon atoms, X represents a cyano, lower alkoxy, carbo(lower allcoxy), carbonamido, acyl, acyloxy, acylamide, amino, alkylamino, dialkylamino, or monocyclic aryl radical, n is 1 or 2, and the nuclei D and B may carry non-ionogenic snbstituents.

The monoor bi-cyclic aromatic radical represented by D may be carbocyclic, for example benzene or naphthalene, or heterocyclic, for example thiazole or benzthiazole and may carry non-ionogenic subs-tituents for example nitro-, cyano-, thiocyano-, methylsu1phonyl-, trifluoromethyl-, 'sulphamyl and halogenosuch as chloroor bromo-.

As examples of non-ionogenic substituents which may be carried by the benzene nucleus B there may be mentioned alkyl groups such as methyl or ethyl, halogen atoms such as chlorine or bromine, alkoxy groups such as methoxy and ethoxy, acylamido groups such as acetamido, and trifluoromethyl groups.

As examples of substituted and unsubstituted groups which may be represented by R there may be mentioned methyl, ethyl, propyl, butyl, cyanoethyl, acetoxyethyl, carbethoxyethyl, methoxyethyl, carbonam-idoethyl, benzyl and p-nitrobenzyl.

As examples of dior tri-valent aliphatic radicals which may be represented by A there may be mentioned the radicals CH -CH CH CH CH CH and As specific examples of radicals which may be represented by X there may be mentioned methoxy, ethoxy,

carbomethoxy, carbet-hoxy, methylcarbonyl, acetoxy, acetamido, ethylamino, diethylamino, phenyl and p-nitrophenyl.

According to 'a further feature of the invention we 3,097,198 Patented July 9, 1963 "ice formula wherein E, R, A, A, X and n have the meanings stated above.

As specific examples of amines of the formula D-NH which may be used in the process of the inventionthere may be mentioned p-nitroaniline, 2-chloro-4-nitroaniline, 2-chloro-4-methylsulphonylaniline, 2-cyano-4-nitroanilinc, 2tr-ifluoromethyl 4 nitroaniline, 1-naphthylamine-4-sulphonami-de, 2-amino 6 methylsulphonylbenzthiazole, 2- amino-6-nitrobenzthiazole, 2-.amino-6-thiocy-anobenzthiazole, 2-amino-6-cyanobenzthiazole, Z-aminobenzthiazole, p-aminophenylmethylsulphone, p-cyanoaniline, o-cyanoaniline, 2:6-diohloro-4-nitroaniline, 2-chloro-4-cyanoaniline, 2:4-dicyanoaniline, 2:4-dinitroaniline and '2-amino- S-nitrothi-azole.

As specific examples of coupling components which may be used in the process of the invention there may be mentioned N-ethyl-N-fl-carbo(cyanomethoxy) ethylaniline, N ethyl-N-fi-carbo(methylcanbonylmethoxy)ethylanline, N-ethyl-N-fi-canbo(diethylaminoethoxy)ethylaniline, N-ethyl-N-fi-canbo(p-nitrobenzyloxy)ethylaniline, N- ethyl-N-fi-carb o (methoxymethoxy) ethylaniline, N ethyl- N-fi-canbo(carbethoxymethoxy) ethylaniline, N-ethyl-N-ficarbo(carbonamidomethoxy)ethylaniline, N N dimcarbo(cyanomethoxy)ethyllaniline, N-ethyl-N [3 oarbo .(B'cyanoethoxy)-ethylaniline, N-ethyl-N B cube-(5- acetoxyethoxy)ethylaniline, N-me-thyl-N-fl-carbo-(cyanomethoxy)ethyl-m-chloroaniline, N p cyanoethyl-N-pcanbo(cyanomethoxy)ethylaniline, N-,8-acetoxyethyl-N-,8'- carbo(cyanomethoxy)ethyl-m-toluidine, N/3-c-arb0-methoxyethyl N 8-carbo(cyanomethoxy)ethylaniline, N-fimethoxye-thyl-N-fi' carbo-(cyanomethoxy)ethyl-m-toluidine, N-fi-canbon-amidoethyl-N-B'-carb0(cyanomethoxy)- ethylaniline, N-ethyl-N-p-carbo(cyanomethoxy) -m-chloroaniline, N ethyl N-fi carb0(cyan0meth0Xy) -m-anisidine, N ethyl-Ncanbo(cyanomethoxy)methylaniline, N-ethyl- N-p-canbo(-dicanbemoxymethoxy)ethylaniline, N-ethyl-N- B-oar boUY-aminoethoxy)ethylaniline and N-benzyl-N-ficarbo(cyanonrethoxy)ethylaniline.

The process of the invention may be conveniently brought about by adding an aqueous solution of the diazonium compound to a solution of the coupling component in aqueous sulphuric or hydrochloric acid, if desired in the presence of a water-miscible inert organic solvent such as acetone, then adding an alkaline reagent such as sodium acetate to neutralise mineral acid, stirring until coupling is complete and filtering off the dyestuif which is precipitated.

The coupling components used in the process of the invention may be obtained by reaction of a carboxylic .acid of the formula A-GOOH 3 with a halogeno-compound of the formula HaA(X) wherein Ha stands for a halogen atom, for example chlorine or bromine. Reaction between the carboxylic acid and halogeno compound may be brought about by heating a mixture of chemically equivalent quantifies of the reagents in the presence of a base such as triethylamine. When reaction is complete it is convenient to isolate the product by adding an organic solvent such as ethyl acetate, filtering from the insoluble hyd-rohalide oi the base, removing the solvent by distillation, and if desired distilling the product under reduced pressure.

According to a further feature of our invention we provide a process for the manufacture of the new waterinsoluble azo-dyestuffs as hereinbefore defined which comprises condensing a carboxylic acid of the formula RI DN=N N \AO OH wherein D, E and A have the meanings previously stated and R stands for a lower alkyl or aralkyl group either of which may carry non-ionogenic substituents or for the group ACOOH, with a halogeno compound of the formula HaA(X) wherein A, X and n have the meaning previously stated and Ha stands for a chlorine or bromine atom.

Condensation between the carboxylic acid of the above formula and the halogeuo compound may conveniently be brought about by heating (for example for 18 hours) a mixture of the two reagents in [the presence of a base, such as triethylamine and an inert solvent for the dyestufi for example ethyl acetate. The hydrohalide of the base may then be filtered off and the dyestuif isolated by evaporation of the solvent.

According to yet a further feature of the invention we provide a process for the manufacture of those new Wateninsoluble azo-dyestufis as hereinbefore defined wherein X represents an acylamido radical which comprises acyl-ating a water-insoluble azo-dyestufl as hereinbefore defined wherein X represents an amino radical by treatment with an acid chloride or anhydride.

As examples of acid chlorides and anhydrides which may be used in this process of the invention there may be mentioned acetyl chloride, propionyl chloride and acetic anhydride.

This process of the invention may conveniently be brought about by heating (for example boiling under reflux) a mixture of the dyestufi wherein X represents an amino radical with the acid chloride or anhydride and pyridine. When acylation is complete (for example afiter heating for 30 minutes) the mixture may be poured into water and the acylated dyestufl isolated by filtration and washing.

The new water-insoluble az-o dyestufis, as hereinbefore defined, are valuable for dyeing textile materials comprising artificial fibres, for example cellulose acetate rayon, cellulose triacetate and polyester fibres. For dyeing such textile materials it is preferred to use the new azo dyestuffis in a finely dispersed form which may be obtained by milling the azo dyestuffs with water and a dispersing agent, for example the \disodium salt of methylene dinaphthalene sulphonic acid. If desired, the so-obtained dispersed aqueous paste of the dyestuff may be dried to form a re-dispersible powder which may be obtained in a non-dusting form by any of the processes known for forming non-dusting powders.

The new water-insoluble azo dyestuifs have excellent waflinity for textile materials comprising artificial fibres which they dye in orange Ito 'blue shades possessing very good iastness to light, washing and to dry heat treatments.

Those new water-insoluble azo dyestuffs as hereinbefore defined in which X stands for a carbalkoxy group or especially for a cyano-group have exceptionally high affinity for aromatic polyester textile material on which 4 dyeings of extremely bright and solid hue may be obtained, possessing excellent fastness to light, to washing and to dry heat treatments.

Those new water-insoluble azo dyestufls as hereinbefore defined in which D represents a p-nitrophenyl nucleus which may be further substituted have excellent fastness to light.

Those new water-insoluble azo dyestuffs as hereinbefore defined in which D represents a 2-benzthi-azyl nucleus which maybe further substituted have exceptionally good fastness to dry heat treatments.

The invention is illustrated but not limited by the following examples in which the parts are by weight.

Example 1 A solution of 2.62 parts of p-nitroaniline in a mixture of 8 parts of water and 8 parts of 10 N hydrochloric acid at 90 C. is added to a stirred mixture of 20 parts of water and parts of ice. A solution of 1.4 parts of sodium nitrite in 9.5 parts of water is added immediately afterwards. The mixture is stirred for 15 minutes and then excess nitrous acid is removed by addition of a little sulphamic acid. The mixture is filtered and the solution .added dropwise during 15 minutes to 4.41 parts of N-ethyl N [,B-carbo(cyanomethoxy)ethyl] aniline in a mixture of 50 parts of water, 3 parts of 10 N hydrochloric acid and 50 parts of acetone to produce a clear solution, between 5 C. and 10 C. Saturated sodium acetate solution is then added until the mixture is no longer acid to Congo red test paper and the mixture is then stirred for 30 minutes. The product is filtered off, reslurried with 300 parts of water which is then made alkaline by addition of soda ash, refiltered, washed with water and dried. 4 nitro 4 [N ethyl-N-fi-carbo(cyanomethoxy) ethylamino]azobenzene is obtained in the form of a red powder which when dispersed in water by milling with the disodium salt of methylene dinaphthylene sulphonic acid dyes aromatic polyester textile materials in bright scarlet shade-s of solid hue having excellent fastness to dry heat and light.

In place of 4.41 parts'of N-ethyl-N-[jS-carbo(cyanomethoxy)ethyH-aniline as coupling component in Example 1 there may be used an equivalent weight of one of the coupling components listed below. The products all dye aromatic polyester textile material in shades which hailregitl ery good fastness to dry heat and excellent fastness to i t.

Shade on EX. Couplmg component aromatic polyester textile material 2. N -ethyl -N-fi -carbo (methylcarbonyl-meth Scarlet.

oxy)ethylan1line 3- N ethyl N -,8- earbo (dicarbethoxymethoxy) Pink. 4 N iii i i r b -e y Scar o -dieth laminoeth v ethylaniline (ls y oxy) Omuce 5. N; etl yl-N -;S -earbo(p -nitrobenzyloxy)ethyl D0.

111 me. 6. N z-letflhyl -N -B-carbo(methoxymethoxy)ethyl- Scarlet.

11 inc 7. N N -di[fl-carbo (eyanomethoxy)cthyl]aniline Oran e. 8- N et l1n yl-N-fl-earbo- (B-cyanomethoxy) ethylscarl t.

am me. 9.-" N -ethyl-N-fl-carho- (carbonamidomethoxy) Do.

ethylanllme. 10. N -cth yl-N -fl-carbo- (fl-acetoxyethoxy)ethy1- Do.

aniline. 11. N pl-lc lzgn iethyhN -,B-carbo- (cyanomethoxy) Reddish-orange.

y 111 me. 12. N-methyl-N-B.-carbo- (cyanomethoxy) -ethyl- Do. 13 Nng-chlrgioanilitrlie. V

. -me oxye lyl-fl -carboc anomethox Red.

ethyl-m-toluidine. y y) 14- N-etiyl-N-carbo- (cyanomethoxy)methylani- Reddish-orange.

n 15- N ibenzyl-N -,S-earbo(eyanomethoxy)ethylani- Do.

me. 16. N -,8-acetoxyetl 1yl-N -fl-carbo (cyanomethoxy) Scarlet.

ethyl-m-tolulcline.

Example 17 The diazo solution obtained from 3.45 parts of p-nitroaniline by the method described in Example 1 is added dropwise during 15 minutes to a solution of 5.1 parts of N-ethyl-N-fi-carboxyethylaniline in a mixture of 12.5 parts of water and 3 parts of 10 N hydrochloric acid, at between C. and C. 4 N sodium acetate solution is added until the mixture is no longer acid to Congo red .test paper and the mixture is then stirred for 30 minutes. The product is filtered off, washed with water and dried.

5.5 parts of the product obtained in this way are dissolved in 300 parts of ethyl acetate; 1.6 parts of triethylamine and 2.95 parts of ethyl chloroacetate are added and the mixture is boiled under reflux for 18 hours, then filtered. The solution is evaporated to a small volume, cooled and the solid product is filtered ofl? and dried. 4-nitro-4- [N-ethyl-N-fi-carbo (carb ethoxymeth oxy) ethylamino]-azobenzene is obtained in the form of a red powder which when dispersed in Water dyes polyethylene terephthalate fibre in bright scarlet shades of solid hue, having very good fastness to dry heat and to light.

Example 18 To a warm solution of 2.59 parts of 2 chloro-4-nitroaniline in 20 parts of glacial acetic acid is added with stirring 4.5 parts of 10 N hydrochloric acid. The mixture is cooled to 10 C. and a solution of 1.1 parts of sodium nitrite in 7.5 parts of water, previously cooled to 5 C., is quickly added. The mixture is stirred at between 5 C. and 10 C. for minutes, then diluted with parts of cold water and excess nitrous acid removed by addition of a little sulphamic acid. The diazo solution so obtained is added during 15 minutes to a solution of 3.48 parts of N-ethyl-N-fi-carbo(cyanomethoxy)ethylaniline in a mixture of 50 parts of water, 3 parts of 10 N hydrochloric acid and 50 parts of acetone. Saturated sodium acetate solution is then added until the mixture is no longer acid to Congo-red test paper and the mixture is stirred for 2 hours. The product is then isolated by a procedure exactly similar to that described for the product of Example 1.

2-chloro-4-nitro-4' [N-ethyl-N-p-carbo cyanomethoxy) ethylamino]-azobenzene is obtained in the form of a red powder which when redispersed in water, dyes aromatic polyester textile material in red shades of solid hue having very good fastness to dry heat and to light.

The following table gives further examples of the shades obtained on aromatic polyester textile materials by using the 'dyestuifs obtained by 'diazotising the amines listed in the second column of the table and coupling with the coupling components listed in the third column of the table by the method described in Example 18. All the dyestuffs have very good fastness to dry heat and excellent iastness to light.

6 Example 27 A solution of nitrosyl sulphuric acid is prepared by adding 1.4 parts of sodium nitrite to 22 parts of concentrated sulphuric acid during 30 minutes, while the temperature is maintained at between 20 C. and 27 C. This solution is added to a rapidly stirred suspension of 4.56 parts of 2-amino-6-methylsulphonylbenzthiazole in a mixture of 27 parts of sulphuric acid and 5 parts of water which is stirred in a freezing mixture to maintain the temperature below 3 C. 40 parts of water is added to the resulting mixture, keeping the temperature below 10 C. and the mixture is then stirred in an ice bath for 30 minutes. The resulting diazonium solution is added to 5.58 parts of N-ethyl-N-fl-carbo-(carbethoxymethoxy) ethylaniline in parts of water, 10 parts of 2 N hydrochloric acid and suflicient acetone to produce a clear solution at 010 C. 50 parts of 1 0 N sodium hydroxide is then added maintaining the temperature below 10 C. After stirring the mixture for a further hour, the solid product is filtered oif, reslurried with 300 parts of water which is then made alkaline by addition of soda ash, refiltered, washed with water and dried. The product is 4-[-ethyl-N-;8-carbo (oarbethoxymethoxy) ethylamino] 6' methy-lsulphonylbenzeneazo(2') benzthiazole. When redispersed in water by milling with the disodiumsalt of methylene dinaphthylene sulphonic acid it dyes polyethylene terephthalate fibre in bright red shades of good solidity which have exceptionally good f-a-stness to dry heat and very good fast ness to light.

The following table gives further examples of the shades obtained on aromatic polyester textile material by using the dyestuffs obtained by diazotising, the amines listed in the second column of the table and coupling with the coupling components listed in the third column of the table by the method described in Example 27. All the dyestuffs have exceptionally good fastness to dry heat and very good fastness to light.

Shade on aro- Ex. Amine Coupling component matie polyester textile material 28-- Z-amino-B-methyl- N-ethyl-N-fl-earbo-(rne- Red.

sulphonylbenzthoxymethoxy)ethylanithiazole. line.

29-- N-ethyl-N-fl-earbo-(cyano- Red.

methoxy)-ethy1aniline.

30.- do N-ethyl-N-fl-carbo-(meth- Red.

ylcarbonyl-methoxy) ethylanlline.

31-- do N-ethyl-N-fl-carbo(dicarb- Red.

ethoxyrnethoxy)-ethylaniline.

32-- 2-amino-6-nitr0-benz- N-ethyl-N-B-carbo(cyanome- Red.

thiaz e. thoxy)-ethylaniline. 33-- 2-amino-txcyanodo Red. benzthiazole. 34 2-amin0-6thi0cydo Red.

anobenzthiazole.

35-- do N :N-di-[B-carbo-(cyanome- Orange-red.

thoxy)-ethyl]aniline.

36 do N-ethyl-N-B-carbo-(B-cya- Red.

noethoxy)-ethylaniline.

37.- do N-ethyl-N-fl-earbo-(carbon- Red.

iiirnidomethoxymthylani- 38 do N-ethylN-fl-earbo-(flacetox- Red.

yethoxy)-ethylaniline.

39-- 2-aminobenzthia- N-ethyl-N-fl-earbo-(cyano- Red.

zole. methoxy)ethylaniline.

Example 40 1.81 parts of sodium nitrite are added to 36 parts of concentrated sulphuric acid at between 2 C. and 27 C. during 30 minutes. 4.15 parts of Z-amino-S-nitrobenzonitrile is then added between 20 C. and 25 C. during 1 hour. After stirring for a further two hours, the solution is poured into a mixture of parts of ice and 30 parts of water and the resulting solution filtered. The diazonium solution so obtained is added to a stirred solution of 6.25 parts of N-ethyl-N-. -carbo-(methylcarbonylrnethoxy)-ethylaniline in 125 parts of water and 15 parts of 2 N hydrochloric acid, at between 5 C. and 10 C.

7 The mixture is neutralised to Congo red paper by addition of saturated aqueous sodium acetate solution, then stirred for 30 minutes. The solid product is filtered oil, reslurried with 300 parts of water which is then made alkaline by addition of soda ash, refiltered, washed with water and dried.

The product is 4-nitro-2-cyano-4'-[N-ethyl-N-5-carbomethylcarb onylmethoxy) ethylamino] -azob enze ne.

When redispersed in water it dyes aromatic polyester textile material in reddish violet shades of solid hue which have good fastness to dry heat and to light.

In place of N-ethyl-N-p-carbo(methylcarbonylmethoxy)-ethylaniline as coupling component in this example may be used an equivalent of one of the coupling components listed below. The products obtained all dye polyethylene terephthalate fibre in shades which have good fastness to dry heat and to light.

Shade on Ex. Coupling component aromatic polyester textile material 41 Reddish violet.

N iethyl-N -B-carb(cyanomethoxy)-ethylani- 42.-- N ethyl N fi carbo(carbethoxymethoxy)- Do.

ethylaniline 43- N ethyl N 8 carbo(methoxymethoxy)- Violet.

ethylaniline 44 NzN-di-[carbo(cyanomethoxy)ethyH-aniline. Reddish-hrown.

46 N-ethyl-N- -carbo(carbonamidomethoxy)- Reddish-brovm.

ethylaniline.

Example 47 The product obtained by coupling diazotised 2-amino-5 nitrobenzotrifiuoride with N-ethyl-N-fi-carbo(cyanomethoxy) ethylaniline by a procedure similar to that described in Example 40, dyes polyethylene terephthalate fibre in bluish-red shades of good fastness to dry heat and to light.

Example 48 0.75 part of sodium nitrite are added during minutes to 9 parts of sulphuric acid, at -30 C. The resulting solution is cooled to 5 C. and a mixture of 8.5 parts of acetic acid and 1.5 parts of propionic acid is added during 20 minutes at 515 C. The solution is cooled to 0 C. and 1.45 parts of Z-amino-S-nitrothiazole is added during 20 minutes at 05 C. A mixture of 8.5 parts of acetic acid and 1.5 parts of propionic acid is then added dropwise over 20 minutes at 0-5 C. and the resulting mixture stirred at this temperature for 3 hours. This solution is added during 15 minutes to a solution of 2.76 parts N B-methoxyethyl N 5 carbo (cyanomethoxy)ethylm-toluidine in 70 parts of water and 6 parts of 2 N hydrochloric acid, stirring at 01'0 C. After stirring the mixture for a further 1 hour, the product is filtered ofi, reslurried with water and made alkaline with soda-ash, refiltered, Washed with water until the washings are free of alkali, and finally dried.

The product is 2-methyl-4-[N-p-methoxyethyl-N-B- carbo (cyanornethoxy)ethylamino] 5' nitro benzeneazo(2')-thiazole. When redispe-rsed in water it dyes aromatic polyester textile materials in reddish-blue shades of very good fastness to dry heat.

Example 49 Example 50 2.4 parts of the dyestuif of Example 49 is boiled under reflux for 30 minutes in a mixture of parts of pyridine and 5 parts of acetic anhydride. The solution is poured .into 300 parts of water and the precipitated dyestutl is '8 filtered oil and dried. 4-nitro-4'-[N-ethyl-N-fi-carbo-(B acetamidoethoxy)ethylamino1azo-benzene is obtained, which whenrdispersed in water, dyes aromatic polyester textile materials in scarlet shades.

The coupling components used in the above examples may be prepared as follows: 7

N-ethyl N fl carbocyanornethoxyethylaniline. To a mixture of 29 parts of N-ethyl-N-fl-carboxyethylaniline and 20 parts of triethylamine, 15 parts of chloroacetonitrile is added. The mixture is heated to between C. and C. for 1 hour, then extracted with 500 parts of ethyl acetate. The solution is filtered, then extracted with 1 00 parts of 10% aqueous sodium bicarbonate solution and dried over magnesium sulphate. The solvent is removed by distillation and the product distilled at a pressure of 0.1 millimetre of mercury, collecting the fraction boiling at -50 C. The oil so-obtained has the following analysis: Found, C, 67.4; H, 7.1; C H O N requires C, 67.2; H, 6.9%.'

By using other halogeno compounds in place of the chloroacetonitrile used above, other coupling components may be obtained. Thus there may be obtained:

N-ethyl N ,8 carbo(methylcarbonylmethoxy)ethylan-iline from chloroacetone.

N-ethyl-N-p carbo (dica-rbethoxymethoxy) ethylaniline from bromodiethylmalonate.

N-ethyl N ,B-carbo(diethylaminoethoxy)ethylaniline from N:N-diethyl-Bchloroethylamine.

N-ethyl-N-fl-carbo (p-nitrobenzyloxy) ethylaniline from p-nitroben'zyl chloride.

N-ethyl-N-fi-carbo(methoxymethoxy)ethylaniline from chlorodimethyl ether.

N-ethyl N fl-carbo(carbethoxymethoxy)ethylaniline from ethylchloroacetate.

N-ethyl-N-fl-carbo (p'-cyanoethoxy)ethylaniline from fl-chloropropionitrile.

N-ethyl N fi-carbo-(carbonamidomethoxy) ethy laniline from chloroace tamide.

N-ethyl-N-B-carbo-(fl-acetoxyethoxy)ethylaniline from Bohloroethylacetate.

N-ethyl-N-fi-carbo (,8'-aminoethoxy)ethylaniline from p-chloroethylamine.

By using chloroacetonitrile and other carboxylic acids in place of the N-ethyl N 3 carboxyethylaniiine used above, other coupling components may be obtained. Thus there may be obtained:

N-fi-cyanoethyl-N-ficarbo (cyanomethoxy)ethylaniline from N-fi-cyanoethyl-N-fl' carboxyethylaniline, which may itself be obtained by heating N-fl-carboxyethylaniline with :acrylonitrile in the presence of acetic acid.

N-methyl-N-fl-carbo (cyanomethoxy)ethyl-m-chloroaniline from N-methyl-N-fi-carboxyethyl-m-chloroaniline, which may itself be obtained by heating N-methyl-mchloroaniline with ethyl acrylate in the presence of cuprous chloride and acetic acid and hydrolysing the prodm-toluidine from N-fi-methoxyethyl N ficarboxyethylm-toluidine, which may itself be obtained by heating N-,9- methoxyethyl-m-toluidine with ethyl acrylate in the presence of cuprous chloride and acetic acid, and hydrolysing the product with aqueous alkali. I

N-ethyl-N-carbo (cyanomethoxy)methylaniline from N-ethyl-N-carboxymethylaniline, which may itself be obtained :by condensing N-ethylaniline with ethyl chloracetate in the presence of calcium carbonate and hydrolysing the product with aqueous alkali.

N-benzyl N-B carbo(cyanomethoxy) ethylaniline from N-benzyl-N-B-carboxyethylaniline, which may itself be obtained -by reacting N-benzylaniline with ethyl acrylate in acetic acid, and hydrolysing the product with aqueous alkali.

N-ethyl N:N-di[,B-carbo(cyanomethoxy)ethyl]aniline from NzN-di-fl-(carboxyethyl) aniline.

N-fiaacetoxyethyl N B-car-b0-(cyanomethoxy) ethylwherein D is a member selected from the class consisting of benzene, thiazole, and benzt-hiazole radicals carrying at least one of the substituents selected from the class consisting of nitro, cyano, thiocyano, methylsulfonyl, trifluorornethyl, and chlorine;

10 R stands for a member selected from the class consisting of lower alkyl, :and cyan'o-, acetoxy-, methoxy-, and earbo(lower alkoxy)- lower alkyl, and benzyl, and the grouping -(CHg)n("]-O(CHz)m-CN m and n are integers from 1 to 2; and E is a member selected from the class consisting of hydrogen, lower alkyl, and chlorine.

2. 4-nitro-4-[N-ethyl N 3 carbo(cyanomethoxy)- e thylanrino] :azobenzen'e.

3. 2-chloro-4-ni tro-4-[N 13 cyanoethyl N-B'-carbo- (cyanornethoxy)ethylaminolazobenzene.

4. 2-chloro-4-cyano-4'- [N-methyl N fi-carbo(cyanomethoxy) ethyl amino] -2'-chloro-azob enzene.

References Cited in the file of this patent UNITED STATES PATENTS McNally et a1 Apr. 17, 1945 Merian Apr. 8, 1958 

1. WATER-INSOLUBLE AZO DYESTUFFS OF THE FORMULA: 